1967 – B.F. Goodrich “Rubber Muscle” – John S. England (American)
A Slightly different tack was taken by B. F. Goodrich in a "rubber muscle" project. If a straight piece of rubber hose with specially wound reinforcing cord is pressurized with a liquid or gas it will bend to form an arc; if more pressure is applied, the curvature increases until the hose becomes a ring. Goodrich made a six-finger "hand" from this special hose that had some prehensile properties.
The below patent is most likely the patent related to the Goodrich "Rubber Muscle".
ACTUATOR John S. England et al
Patent number: 3924519
Filing date: Aug 21, 1968
Issue date: 1975
See full patent details here.
Tags: "Rubber Muscle", 1967, Air Muscle, American, John S. England, Pneumatic Artificial Muscle (PAM), pneumatic end-effector, Pneumatic gripper, pneumatic muscle